From 932df1237b64fcb80c23acb2177bfe659654220a Mon Sep 17 00:00:00 2001 From: Ben Pfaff Date: Mon, 6 Jun 2011 09:43:48 -0700 Subject: [PATCH] stream-ssl: Disable SSL session caching. SSL session caching causes mysterious connection failure problems. Bug #4448. Bug #4501. --- lib/stream-ssl.c | 105 ----------------------------------------------- 1 file changed, 105 deletions(-) diff --git a/lib/stream-ssl.c b/lib/stream-ssl.c index a93c0064..4d7c7c4d 100644 --- a/lib/stream-ssl.c +++ b/lib/stream-ssl.c @@ -49,9 +49,6 @@ VLOG_DEFINE_THIS_MODULE(stream_ssl); -COVERAGE_DEFINE(ssl_session); -COVERAGE_DEFINE(ssl_session_reused); - /* Active SSL. */ enum ssl_state { @@ -140,20 +137,6 @@ struct ssl_stream /* SSL context created by ssl_init(). */ static SSL_CTX *ctx; -/* Maps from stream target (e.g. "127.0.0.1:1234") to SSL_SESSION *. The - * sessions are those from the last SSL connection to the given target. - * OpenSSL caches server-side sessions internally, so this cache is only used - * for client connections. - * - * The stream_ssl module owns a reference to each of the sessions in this - * table, so they must be freed with SSL_SESSION_free() when they are no - * longer needed. */ -static struct shash client_sessions = SHASH_INITIALIZER(&client_sessions); - -/* Maximum number of client sessions to cache. Ordinarily I'd expect that one - * session would be sufficient but this should cover it. */ -#define MAX_CLIENT_SESSION_CACHE 16 - struct ssl_config_file { bool read; /* Whether the file was successfully read. */ char *file_name; /* Configured file name, if any. */ @@ -283,13 +266,6 @@ new_ssl_stream(const char *name, int fd, enum session_type type, if (!verify_peer_cert || (bootstrap_ca_cert && type == CLIENT)) { SSL_set_verify(ssl, SSL_VERIFY_NONE, NULL); } - if (type == CLIENT) { - /* Grab SSL session information from the cache. */ - SSL_SESSION *session = shash_find_data(&client_sessions, name); - if (session && SSL_set_session(ssl, session) != 1) { - interpret_queued_ssl_error("SSL_set_session"); - } - } /* Create and return the ssl_stream. */ sslv = xmalloc(sizeof *sslv); @@ -446,58 +422,6 @@ do_ca_cert_bootstrap(struct stream *stream) return EPROTO; } -static void -ssl_delete_session(struct shash_node *node) -{ - SSL_SESSION *session = node->data; - SSL_SESSION_free(session); - shash_delete(&client_sessions, node); -} - -/* Find and free any previously cached session for 'stream''s target. */ -static void -ssl_flush_session(struct stream *stream) -{ - struct shash_node *node; - - node = shash_find(&client_sessions, stream_get_name(stream)); - if (node) { - ssl_delete_session(node); - } -} - -/* Add 'stream''s session to the cache for its target, so that it will be - * reused for future SSL connections to the same target. */ -static void -ssl_cache_session(struct stream *stream) -{ - struct ssl_stream *sslv = ssl_stream_cast(stream); - SSL_SESSION *session; - - /* Get session from stream. */ - session = SSL_get1_session(sslv->ssl); - if (session) { - SSL_SESSION *old_session; - - old_session = shash_replace(&client_sessions, stream_get_name(stream), - session); - if (old_session) { - /* Free the session that we replaced. (We might actually have - * session == old_session, but either way we have to free it to - * avoid leaking a reference.) */ - SSL_SESSION_free(old_session); - } else if (shash_count(&client_sessions) > MAX_CLIENT_SESSION_CACHE) { - for (;;) { - struct shash_node *node = shash_random_node(&client_sessions); - if (node->data != session) { - ssl_delete_session(node); - break; - } - } - } - } -} - static int ssl_connect(struct stream *stream) { @@ -530,17 +454,6 @@ ssl_connect(struct stream *stream) } else { int unused; - if (sslv->type == CLIENT) { - /* Delete any cached session for this stream's target. - * Otherwise a single error causes recurring errors that - * don't resolve until the SSL client or server is - * restarted. (It can take dozens of reused connections to - * see this behavior, so this is difficult to test.) If we - * delete the session on the first error, though, the error - * only occurs once and then resolves itself. */ - ssl_flush_session(stream); - } - interpret_ssl_error((sslv->type == CLIENT ? "SSL_connect" : "SSL_accept"), retval, error, &unused); shutdown(sslv->fd, SHUT_RDWR); @@ -565,11 +478,6 @@ ssl_connect(struct stream *stream) VLOG_ERR("rejecting SSL connection during bootstrap race window"); return EPROTO; } else { - /* Statistics. */ - COVERAGE_INC(ssl_session); - if (SSL_session_reused(sslv->ssl)) { - COVERAGE_INC(ssl_session_reused); - } return 0; } } @@ -590,8 +498,6 @@ ssl_close(struct stream *stream) * background. */ SSL_shutdown(sslv->ssl); - ssl_cache_session(stream); - /* SSL_shutdown() might have signaled an error, in which case we need to * flush it out of the OpenSSL error queue or the next OpenSSL operation * will falsely signal an error. */ @@ -1009,17 +915,6 @@ do_ssl_init(void) SSL_CTX_set_verify(ctx, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, NULL); - /* We have to set a session context ID string in 'ctx' because OpenSSL - * otherwise refuses to use a cached session on the server side when - * SSL_VERIFY_PEER is set. And it not only refuses to use the cached - * session, it actually generates an error and kills the connection. - * According to a comment in ssl_get_prev_session() in OpenSSL's - * ssl/ssl_sess.c, this is intentional behavior. - * - * Any context string is OK, as long as one is set. */ - SSL_CTX_set_session_id_context(ctx, (const unsigned char *) PACKAGE, - strlen(PACKAGE)); - return 0; } -- 2.30.2